Individual phase temperature monitoring and balance control for smart power stage-based voltage regulator

ABSTRACT

Systems and methods for individual phase temperature monitoring and balance control in a multi-phase voltage regulator may include a plurality of smart power stages including a first smart power stage and a second smart power stage and a voltage regulator controller. The voltage regulator controller may send a first control signal to the first smart power stage to enable the first smart power stage to send a first temperature of the first smart power stage to the voltage regulator controller during a first phase of a switching cycle. The voltage regulator controller may also determine that the first temperature received by the voltage regulator controller corresponds to the first smart power stage based on the first control signal. The voltage regulator controller may further send a second control signal to the second smart power stage to enable the second smart power stage to send a second temperature to the voltage regulator controller during a second phase.

BACKGROUND

Field of the Disclosure

This disclosure relates generally to information handling systems and,more particularly, to a multi-phase voltage regulator for an informationhandling system.

Description of the Related Art

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Information handling systems may include a variety of hardware and/orsoftware components that may be configured to process, store, and/orcommunicate information. Information handling systems may also includeone or more multi-phase voltage regulators to ensure that necessaryelectrical current is consistently supplied to one or more devices inthe information handling system. Typical multi-phase voltage regulatorsmay include a voltage regulator controller and multiple power stages,each power stage may include a temperature output/fault pin (TOUT/FLT)that may allow for temperature monitoring and fault detection of thepower stage. In the typical multi-phase voltage regulator, the voltageregulator controller has only a single temperature monitor pin (TMON)that connects the voltage regulator controller to the multiple powerstages via a shared monitor bus. In this configuration, each TOUT/FLT ofeach individual power stage is wire-ored to the shared monitor bus,which results in the individual power stage that has the highesttemperature to dominate the bus with the highest temperature. Thevoltage regulator controller may not have the knowledge of thetemperatures of each of the other individual power stages or whichindividual power stage has this highest temperature. In addition, whenan individual power stage signals a fault on its TOUT/FLT on the monitorbus, the voltage regulator controller only knows that one or more of themultiple power stage is signaling a fault but it does not know whichone. In a voltage regulator protection scheme, the voltage regulatorcontroller may shutdown all of the power stages, causing a powerdisruption and potential loss of data. This may prevent the voltageregulator controller from monitoring the temperate or detecting anyfaults for an individual power stage.

SUMMARY

In one aspect, a disclosed multi-phase voltage regulator may include aplurality of smart power stages including a first smart power stage anda second smart power stage. The multi-phase voltage regulator may alsoinclude a controller coupled to: the first smart power stage by a firstsignal line and a shared monitor bus, and the second smart power stageby a second signal line and the shared monitor bus. The voltageregulator controller may send a first control signal to the first smartpower stage via the first signal line to enable the first smart powerstage to send a first temperature of the first smart power stage to thevoltage regulator controller during a first phase of a switching cyclecorresponding to the first smart power stage. The voltage regulatorcontroller may also determine that the first temperature received by thevoltage regulator controller via the shared monitor bus corresponds tothe first smart power stage based on the first control signal. Thevoltage regulator controller may also send a second control signal tothe second smart power stage via the second signal line to enable thesecond smart power stage to send a second temperature to the voltageregulator controller during a second phase.

In any of the disclosed embodiments of the multi-phase voltageregulator, the voltage regulator controller may determine that thesecond temperature received by the voltage regulator controllercorresponds to the second smart power stage based on the second controlsignal.

In any of the disclosed embodiments of the multi-phase voltageregulator, the first smart power stage may include a first switch tosend the first temperature to the voltage regulator controller based ona rising edge of the first control signal.

In any of the disclosed embodiments of the multi-phase voltageregulator, the first switch may be controlled by a mono-stablemulti-vibrator.

In any of the disclosed embodiments of the multi-phase voltageregulator, the voltage regulator controller may determine whether thefirst temperature of the first smart power stage is equal to or greaterthan a value of a temperature imbalance threshold. The voltage regulatorcontroller may also, when the first temperature is equal to or greaterthan the value of the temperature imbalance threshold, reduce a firstduty cycle of the first phase and adjust each duty cycle of each of theplurality of the other phases according to a temperature balance controlpolicy.

In any of the disclosed embodiments of the multi-phase voltageregulator, the value of the temperature imbalance threshold may includean average of each temperature of each smart power stage of theplurality of smart power stages.

In any of the disclosed embodiments of the multi-phase voltageregulator, the voltage regulator controller may determine whether thefirst temperature of the first smart power stage is equal to or greaterthan a value of a temperature imbalance threshold. The voltage regulatorcontroller may also, when the first temperature is equal to or greaterthan the value of the temperature imbalance threshold, send a warningthat indicates an imminent fault of the first smart power stage.

In any of the disclosed embodiments of the multi-phase voltageregulator, the first control signal may be a pulse width modulatedsignal.

In another aspect, a disclosed multi-phase voltage regulator may includea plurality of smart power stages including a first smart power stageand a second smart power stage. The multi-phase voltage regulator mayalso include a voltage regulator controller coupled to: the first smartpower stage by a first signal line, a shared signal line, and a sharedmonitor bus, and the second smart power stage by a second signal line,the shared signal line, and the shared monitor bus. The voltageregulator controller may send a first sequence of one or more controlsignals to the first smart power stage via the first signal line. Thevoltage regulator controller may also send a second sequence of one ormore shared control signals that coincide with the first sequence of oneor more control signals to the plurality of smart power stages via theshared signal line to enable the first smart power stage to send a firsttemperature of the first smart power stage to the voltage regulatorcontroller during a first reporting window. The voltage regulatorcontroller may further determine that the first temperature received bythe voltage regulator controller via the shared monitor bus correspondsto the first smart power stage based on the second sequence of the oneor more shared control signals. The voltage regulator controller mayalso send a fourth sequence of one or more shared control signals thatcoincide with a third sequence of one or more control signals to theplurality of smart power stages via the shared signal line to enable thesecond smart power stage to send a second temperature of the secondsmart power stage to the voltage regulator controller during a secondreporting window.

In any of the disclosed embodiments of the multi-phase voltageregulator, the voltage regulator controller may determine that thesecond temperature corresponds to the second smart power stage based onthe fourth sequence of the one or more shared control signals.

In any of the disclosed embodiments of the multi-phase voltageregulator, the first smart power stage may include a detector to sendthe first temperature to the voltage regulator controller based ondetection of the second sequence of the one or more shared controlsignals that coincide with the first sequence of the one or more controlsignals received by the first smart power stage.

In any of the disclosed embodiments of the multi-phase voltageregulator, the voltage regulator controller may determine whether thefirst temperature of the first smart power stage is equal to or greaterthan a value of a temperature imbalance threshold. The voltage regulatorcontroller may also, when the first temperature is equal to or greaterthan the value of the temperature imbalance threshold, reduce a firstduty cycle of the first phase and adjust each duty cycle of each of theplurality of the other phases according to a temperature balance controlpolicy.

In any of the disclosed embodiments of the multi-phase voltageregulator, the value of the temperature imbalance threshold may includean average of each temperature of each smart power stage of theplurality of smart power stages.

In any of the disclosed embodiments of the multi-phase voltageregulator, the voltage regulator controller may determine whether thefirst temperature of the first smart power stage is equal to or greaterthan a value of a temperature imbalance threshold. The voltage regulatorcontroller may also, when the first temperature is equal to or greaterthan the value of the temperature imbalance threshold, send a warningthat indicates an imminent fault of the first smart power stage.

In any of the disclosed embodiments of the multi-phase voltageregulator, the first sequence of the one or more control signals may bepulse width modulated signals.

In yet another aspect, a disclosed multi-phase voltage regulator mayinclude a plurality of smart power stages including a first smart powerstage and a second smart power stage. The multi-phase voltage regulatormay also include a voltage regulator controller coupled to: the firstsmart power stage by a shared signal line and a shared monitor bus, andthe second smart power stage by the shared signal line and the sharedmonitor bus. The voltage regulator controller may send a first sequenceof a first number of shared control signals to the plurality of smartpower stages via the shared signal line to enable the first smart powerstage corresponding to the first number to send a first temperature ofthe first smart power stage to the voltage regulator controller during afirst reporting window. The voltage regulator controller may alsodetermine that the first temperature received by the voltage regulatorcontroller via the shared monitor bus corresponds to the first smartpower stage based on the first sequence of the first number of sharedcontrol signals. The voltage regulator controller may further send asecond sequence of a second number of shared control signals to theplurality of smart power stages via the shared signal line to enable thesecond smart power stage corresponding to the second number to send asecond temperature of the second smart power stage to the voltageregulator controller during a second reporting window.

In any of the disclosed embodiments of the multi-phase voltageregulator, the voltage regulator controller may determine that thesecond temperature received by the voltage regulator controller via theshared monitor bus corresponds to the second smart power stage based onthe second sequence of the second number of shared control signals.

In any of the disclosed embodiments of the multi-phase voltageregulator, the first smart power stage may include a detector to sendthe first temperature to the voltage regulator controller based on acount of each falling edge of the first sequence of the first number ofshared control signals received from the voltage regulator controllermatches the first number corresponding to the first smart power stagewhen a temperature request duration is reached.

In any of the disclosed embodiments of the multi-phase voltageregulator, the voltage regulator controller may determine whether thefirst temperature of the first smart power stage is equal to or greaterthan a value of a temperature imbalance threshold. The voltage regulatorcontroller may, when the first temperature is equal to or greater thanthe value of the temperature imbalance threshold, reduce a first dutycycle of the first phase and adjust each duty cycle of each of theplurality of the other phases according to a temperature balance controlpolicy.

In any of the disclosed embodiments of the multi-phase voltageregulator, the voltage regulator controller may determine whether thefirst temperature of the first smart power stage is equal to or greaterthan a value of a temperature imbalance threshold. The voltage regulatorcontroller may also, when the first temperature is equal to or greaterthan the value of the temperature imbalance threshold, send a warningthat indicates an imminent fault of the first smart power stage.

Other technical advantages will be apparent to those of ordinary skillin the art in view of the following specification, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram of selected elements of an embodiment of aninformation handling system;

FIG. 2A is a circuit diagram of selected elements of an embodiment of amulti-phase voltage regulator;

FIG. 2B is a circuit diagram of selected elements of an embodiment of asmart power stage of a multi-phase voltage regulator;

FIG. 3 is a timing diagram of phase control and monitor temperature bussignals for selected phases of an embodiment of a multi-phase voltageregulator;

FIG. 4A is a circuit diagram of selected elements of an embodiment of amulti-phase voltage regulator having a shared signal line;

FIG. 4B is a circuit diagram of selected elements of an embodiment of asmart power stage of a multi-phase voltage regulator having a sharedsignal line;

FIG. 5 is a timing diagram of shared signal line, phase signal line, andmonitor bus signals for selected elements of an embodiment of amulti-phase voltage regulator having a shared signal line;

FIG. 6A is a circuit diagram of selected elements of an embodiment of amulti-phase voltage regulator with smart power stage pin strapping;

FIG. 6B is a circuit diagram of selected elements of an embodiment asmart power stage of a multi-phase voltage regulator with smart powerstage pin strapping;

FIG. 7 is a timing diagram of shared signal line signals and phasefalling edge counts for selected elements of an embodiment of amulti-phase voltage regulator with smart power stage pin strapping;

FIG. 8 is flowchart depicting selected elements of an embodiment of amethod for individual phase temperature monitoring and balance controlin a smart power stage based multi-phase voltage regulator;

FIG. 9 is flowchart depicting selected elements of an embodiment of amethod for temperature balance control in a smart power stage basedmulti-phase voltage regulator;

FIG. 10 is flowchart depicting selected elements of an embodiment of amethod for individual phase temperature monitoring and balance controlin a smart power stage based multi-phase voltage regulator; and

FIG. 11 is flowchart depicting selected elements of an embodiment of amethod for individual phase temperature monitoring and balance controlin a smart power stage based multi-phase voltage regulator.

DESCRIPTION OF PARTICULAR EMBODIMENT(S)

In the following description, details are set forth by way of example tofacilitate discussion of the disclosed subject matter. It should beapparent to a person of ordinary skill in the field, however, that thedisclosed embodiments are exemplary and not exhaustive of all possibleembodiments.

For the purposes of this disclosure, an information handling system mayinclude an instrumentality or aggregate of instrumentalities operable tocompute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize various forms of information, intelligence, or data forbusiness, scientific, control, entertainment, or other purposes. Forexample, an information handling system may be a personal computer, aPDA, a consumer electronic device, a network storage device, or anothersuitable device and may vary in size, shape, performance, functionality,and price. The information handling system may include memory, one ormore processing resources such as a central processing unit (CPU) orhardware or software control logic. Additional components or theinformation handling system may include one or more storage devices, oneor more communications ports for communicating with external devices aswell as various input and output (I/O) devices, such as a keyboard, amouse, and a video display. The information handling system may alsoinclude one or more buses operable to transmit communication between thevarious hardware components.

For the purposes of this disclosure, computer-readable media may includean instrumentality or aggregation of instrumentalities that may retaindata and/or instructions for a period of time. Computer-readable mediamay include, without limitation, storage media such as a direct accessstorage device (e.g., a hard disk drive or floppy disk), a sequentialaccess storage device (e.g., a tape disk drive), compact disk, CD-ROM,DVD, random access memory (RAM), read-only memory (ROM), electricallyerasable programmable read-only memory (EEPROM), and/or flash memory(SSD); as well as communications media such wires, optical fibers,microwaves, radio waves, and other electromagnetic and/or opticalcarriers; and/or any combination of the foregoing.

As noted previously, current information handling systems may demandmulti-phase voltage regulators that are able to monitor the temperatureand detect a fault of each individual smart power stage, whileconsistently supplying the necessary electrical current to theinformation handling systems and reducing their size. As will bedescribed in further detail, the inventors of the present disclosurehave developed novel circuits and methods disclosed herein forindividual phase temperature monitoring and balance control for a smartpower stage based voltage regulator.

Particular embodiments are best understood by reference to FIGS. 1through 11 wherein like numbers are used to indicate like andcorresponding parts.

Turning now to the drawings, FIG. 1 illustrates a block diagramdepicting selected elements of an embodiment of information handlingsystem 100. As shown in FIG. 1, components of information handlingsystem 100 may include, but are not limited to, a multi-phase voltageregulator 180, a processor subsystem 120, which may comprise one or moreprocessors, and system bus 121 that communicatively couples varioussystem components to processor subsystem 120 including, for example, amemory subsystem 130, an I/O subsystem 140, a local storage resource150, and a network interface 160. System bus 121 may represent a varietyof suitable types of bus structures, e.g., a memory bus, a peripheralbus, or a local bus using various bus architectures in selectedembodiments. For example, such architectures may include, but are notlimited to, Micro Channel Architecture (MCA) bus, Industry StandardArchitecture (ISA) bus, Enhanced ISA (EISA) bus, Peripheral ComponentInterconnect (PCI) bus, PCI-Express bus, HyperTransport (HT) bus, andVideo Electronics Standards Association (VESA) local bus.

In FIG. 1, network interface 160 may be a suitable system, apparatus, ordevice operable to serve as an interface between information handlingsystem 100 and a network 155. Network interface 160 may enableinformation handling system 100 to communicate over network 155 using asuitable transmission protocol and/or standard, including, but notlimited to, transmission protocols and/or standards enumerated belowwith respect to the discussion of network 155. In some embodiments,network interface 160 may be communicatively coupled via network 155 toa network storage resource 170. Network 155 may be implemented as, ormay be a part of, a storage area network (SAN), personal area network(PAN), local area network (LAN), a metropolitan area network (MAN), awide area network (WAN), a wireless local area network (WLAN), a virtualprivate network (VPN), an intranet, the Internet or another appropriatearchitecture or system that facilitates the communication of signals,data and/or messages (generally referred to as data). Network 155 maytransmit data using a desired storage and/or communication protocol,including, but not limited to, Fibre Channel, Frame Relay, AsynchronousTransfer Mode (ATM), Internet protocol (IP), other packet-basedprotocol, small computer system interface (SCSI), Internet SCSI (iSCSI),Serial Attached SCSI (SAS) or another transport that operates with theSCSI protocol, advanced technology attachment (ATA), serial ATA (SATA),advanced technology attachment packet interface (ATAPI), serial storagearchitecture (SSA), integrated drive electronics (IDE), and/or anycombination thereof. Network 155 and its various components may beimplemented using hardware, software, or any combination thereof

As depicted in FIG. 1, processor subsystem 120 may comprise a system,device, or apparatus operable to interpret and/or execute programinstructions and/or process data, and may include a microprocessor,microcontroller, digital signal processor (DSP), application specificintegrated circuit (ASIC), or another digital or analog circuitryconfigured to interpret and/or execute program instructions and/orprocess data. In some embodiments, processor subsystem 120 may interpretand/or execute program instructions and/or process data stored locally(e.g., in memory subsystem 130 and/or another component of informationhandling system). In the same or alternative embodiments, processorsubsystem 120 may interpret and/or execute program instructions and/orprocess data stored remotely (e.g., in network storage resource 170).

Also in FIG. 1, memory subsystem 130 may comprise a system, device, orapparatus operable to retain and/or retrieve program instructions and/ordata for a period of time (e.g., computer-readable media). Memorysubsystem 130 may comprise random access memory (RAM), electricallyerasable programmable read-only memory (EEPROM), a PCMCIA card, flashmemory, magnetic storage, opto-magnetic storage, and/or a suitableselection and/or array of volatile or non-volatile memory that retainsdata after power to its associated information handling system, such assystem 100, is powered down. Local storage resource 150 may comprisecomputer-readable media (e.g., hard disk drive, floppy disk drive,CD-ROM, and/or other type of rotating storage media, flash memory,EEPROM, and/or another type of solid state storage media) and may begenerally operable to store instructions and/or data. Likewise, networkstorage resource 170 may comprise computer-readable media (e.g., harddisk drive, floppy disk drive, CD-ROM, and/or other type of rotatingstorage media, flash memory, EEPROM, and/or other type of solid statestorage media) and may be generally operable to store instructionsand/or data. In system 100, I/O subsystem 140 may comprise a system,device, or apparatus generally operable to receive and/or transmit datato/from/within system 100. I/O subsystem 140 may represent, for example,a variety of communication interfaces, graphics interfaces, videointerfaces, user input interfaces, and/or peripheral interfaces. Asshown, I/O subsystem 140 may comprise touch panel 142 and displayadapter 144. Touch panel 142 may include circuitry for enabling touchfunctionality in conjunction with a display 146 that is driven bydisplay adapter 144.

As will be described in further detail, information handling system 100,or certain components included therein, may be supplied power by one ormore power supply units. The power supply units may supply current toprocessor subsystem 120, memory subsystem 130, I/O subsystem 140, localstorage resource 150, among other components of information handlingsystem 100. A power supply unit may utilize multi-phase voltageregulator 180 to ensure the necessary electrical current is consistentlysupplied to these components, as described in further detail below. Asshown, multi-phase voltage regulator 180 is coupled to processorsubsystem 120 but may be coupled to other components of informationhandling system 100.

Turning now to FIGS. 2A and 2B, a circuit diagram of selected elementsof an embodiment of a multi-phase voltage regulator 200 is illustrated.Multi-phase voltage regulator 200 may be multi-phase voltage regulator180 described above. In FIGS. 2A and 2B, multi-phase voltage regulator200 is shown in a schematic representation and is not drawn to scale orperspective. It is noted that, in different embodiments, multi-phasevoltage regulator 200 may be operated with additional or fewer elements.

As shown in FIG. 2A, components of multi-phase voltage regulator 200 mayinclude, but are not limited to, a voltage regulator controller 202, aplurality of smart power stages 204 including smart power stages 204-1to 204-6, a voltage regulator input voltage (VIN) 236, inductors 208including inductor 208-1 to 208-6, a voltage regulator output voltage240, a load 210, and a capacitor 212. A plurality of signal lines 252including signal lines 252-1 to 252-6 may be coupled between a pluralityof corresponding pulse width modulation (PWM) outputs 222 including PWMoutputs 222-1 to 222-6 of voltage regulator controller 202 and aplurality of corresponding PWM inputs 232 including PWM inputs 232-1 to232-6 of smart power stages 204-1 to 204-6 respectively. For example,signal line 252-1 is coupled between PWM output 222-1 of voltageregulator controller 202 and PWM input 232-1 of smart power stage 204-1.Each signal line may be a PWM signal line and may carry a PWM controlsignal having a voltage at a high voltage level, a low voltage level, ora tristate voltage level. A monitor bus 254 is coupled between atemperature sense/fault pin (TSENSE) 224 of voltage regulator controller202 and a plurality of corresponding temperature output/fault pins(TOUT/FLT) 234 including TOUT/FLT 234-1 to 234-6 of smart power stages204-1 to 204-6. For example, monitor bus 254 is coupled between TSENSE224 of voltage regulator controller 202 and TOUT/FLT 234-1 of smartpower stage 204-1. Monitor bus 254 is also coupled between TSENSE 224and TOUT/FLT 234-3 of smart power stage 204-3. In this configuration,monitor bus 254 is a shared bus. VIN 236 is coupled to each of the smartpower stages 204 to supply power to each smart power stage 204. Each oneof the inductors 208 is coupled between a switching node output (SW) 238of a corresponding smart power stage 204 and the load 210. SW 238 may becoupled to a main circuit of a synchronous buck converter, connecting ahigh side field effect transistor (FET), a low side FET, and outputinductor. The corresponding smart power stage 204 supplies power to load210 via its corresponding inductor 208.

As shown in FIG. 2B, components of each smart power stage 204 of theplurality of smart power stages 204 may include a power circuit 250having a driver, a high side field effect transistor (FET), and a lowside FET, other logic 254, and a switch 242 having a one shot 244, whichcauses switch 242's on/off waveform to behave like a mono-stablemulti-vibrator. In operation, switch 242 will turn on with a rising edgeof a control signal received at PWM input 232 of the smart power stage204 and will turn off after a pre-determined duration. When a switch 242is turned on, the corresponding smart power stage 204 may send atemperature of smart power stage 204 at TOUT/FLT 234 of correspondingsmart power stage 204 to voltage regulator controller 202 via monitorbus 254 during a reporting window, where the duration of the reportingwindow is from the rising edge of the control signal received to whenswitch 242 turns off after the pre-determined duration. This reportingwindow may be set to a duration that allows voltage regulator controller202 to receive the temperature before requesting any other smart powerstage 204 to report its temperature 252, so that the requested smartpower stage 204 is the only one reporting its temperature on monitor bus254 during the reporting window and does not overlap with any othersmart power stage 204 reporting its temperature. Temperature 252 isbuffered through a super diode circuit, also referred herein as a zerodrop diode circuit, including a diode 246 and an amplifier 248.Operating in this manner, allows voltage regulator controller 202 tocontrol which smart power stage 204 sends its temperature 252 tocontroller 202 and to determine that the temperature received at TSENSE224 via monitor bus 254 corresponds to that particular smart power stage204.

Referring back to FIG. 2A, during normal operation mode, the output ofTOUT/FLT 234 of a particular smart power stage 204, e.g. TOUT/FLT 234-1,may be reporting temperature defined by an equation 8 mV/C+0.8V, where Cis the die Celsius temperature and 0.8V corresponds to 25 C at baseline.When a particular smart power stage 204 is fault signaling, TOUT/FLT 234of the particular smart power stage 204 may be pulled high, e.g. 3.3V,when the particular smart power stage 204 detects one or more of an overtemperature protection (OTP) fault, an over current protection (OCP)fault, a FET shoot through fault, among other faults.

During operation, voltage regulator controller 202 may monitor thetemperature of each individual smart power stage 204 of smart powerstages 204-1 to 204-6 to provide phase to phase temperature balancecontrol of smart power stages 204-1 to 204-6 and to detect an imminentfault of a particular smart power stage 204, described in further detailbelow. Multi-phase voltage regulator 200 may have an associatedswitching cycle including multiple phases that are distributed acrossone switching cycle, where each of the multiple phases corresponds toeach of the plurality of smart power stages 204. In an exemplaryembodiment, if a switching frequency of a four phase voltage regulatoris 500 kHz, and therefore, the switching cycle is 2 μseconds, the risingedge of four PWM signals happen within 500 ns (2 μs/4) of each other.

During operation, voltage regulator controller 202 may send a firstcontrol signal to smart power stage 204-1 via signal line 252-1 toenable smart power stage 204-1 to send a first temperature of smartpower stage 204-1 to voltage regulator controller 202 during a firstphase of the switching cycle corresponding to smart power stage 204-1.In response to receiving the first control signal from voltage regulatorcontroller 202 at PWM input 232-1 via signal line 252-1, switch 242-1will turn on with the rising edge of the first control signal and smartpower stage 204-1 will send the first temperature of smart power stage204-1 to voltage regulator controller 202 via monitor bus 254 during theduration of the reporting window. Voltage regulator controller 202 mayreceive the first temperature of smart power stage 204-1 from smartpower stage 204-1 via monitor bus 254 during the reporting window.Voltage regulator controller 202 may also determine that the firsttemperature received by voltage regulator controller 202 corresponds tosmart power stage 204-1 based on the first control signal and thatvoltage regulator controller 202 has not requested any other smart powerstages 204 to report their temperatures during the reporting window.When the reporting window closes, switch 242-1 turns off and smart powerstage 204-1 stops reporting its temperature on monitor bus 254. Voltageregulator controller 202 may then make another temperature reportingrequest in a similar manner as previously described. For example,voltage regulator controller 202 may send a second control signal tosmart power stage 204-2 via signal line 252-2 to enable smart powerstage 204-2 to send a second temperature to voltage regulator controller202 during a second reporting window. Similarly, voltage regulatorcontroller 202 may determine that the second temperature corresponds tosmart power stage 204-2 based on the second control signal and thatvoltage regulator controller 202 has not requested any other smart powerstages 204 to report their temperatures during the second reportingwindow. The interaction between voltage regulator controller 202 andeach of the smart power stages 204 is shown in more detail in FIG. 3.

Turning now to FIG. 3, a timing diagram 300 of phase signal line andmonitor bus signals for selected elements of an embodiment of amulti-phase voltage regulator (e.g. multi-phase voltage regulator 200)is illustrated. The top three portions of timing diagram 300 show thethree control signals sent by voltage regulator controller 202 to eachcorresponding smart power stage 204-1 (phase 1), 204-2 (phase 2), and204-3 (phase 3) via signal lines 252-1, 252-2, and 252-3 respectively,where smart power stage 204-1 has a temperature of 100° C., smart powerstage 204-2 has a temperature of 90° C., and smart power stage 204-3 hasa temperature of 85° C. The fourth portion of timing diagram 200 showsthe voltage level of monitor bus 254 corresponding to the temperature ofeach smart power stage, 204-1, 204-2, and 204-3, on monitor bus 254during its specific reporting window. For example, the rising edge ofthe first control signal on signal line 252-1 causes smart power stage204-1 to send its temperature to voltage regulator controller 202 bydriving the voltage level of monitor bus 254 corresponding to thetemperature 100° C. during a first reporting window, as depicted bydotted line arrow 311. As shown, voltage regulator controller 202 sentno other control signals via signal lines 252-2 and 252-3 to smart powerstages 204-2 and 204-3 to send their temperatures, so only thetemperature of smart power stage 204-1 is shown on monitor bus 254during the first reporting window. Similarly, the rising edges of thesecond and third control signals causes smart power stages 204-2 and204-3 to send their temperatures to voltage regulator controller 202 bydriving the voltage level of monitor bus 254 corresponding totemperatures 90° C. and 85° C. during a second and a third reportingwindow respectively, as depicted by dotted line arrows 313 and 315. Forreference, the fifth portion of timing diagram 200 labeled MONITOR BUSW/O SWITCH shows the case where smart power stages of a voltageregulator controller do not include switch 242 and, as such, each smartpower stage sends its temperature to the voltage regulator controller bydriving the voltage level of the monitor bus corresponding to each ofthe respective temperatures 100° C., 90° C., and 85° C. during the samereporting window. In this case, the highest temperature 100° C.dominates the monitor bus and the temperature of each of the smart powerstages is unknown to the voltage regulator controller.

Referring back to FIG. 2A, in one or more embodiments, voltage regulatorcontroller 202 may monitor the temperature of each individual smartpower stage 204 of the plurality of smart power stages 204 for phase tophase temperature balance control of the plurality of smart power stages204. The temperature of each individual smart power stage 204 may bequite different than each of the other individual smart power stages 204due to a difference in cooling and airflow at each of the individualsmart power stages 204. For example, the physical location, e.g. center,middle, edge, side, amongst other locations, of each individual smartpower stage 204 may be different between each of the other smart powerstages 204, which may result in different levels of airflow at eachlocation leading to differences in the level of cooling provided. Theloads of each of the smart power stages 204 may also be different,resulting in further differences in temperature. In an exemplaryembodiment, temperature differences of 10° C. or higher betweenindividual smart power stages 204 located in center positions and thoselocated in side positions during heavy load conditions. Thesetemperature differences may lead to decreased reliability and lifetimeof some of smart power stages 204. In order to address these issues,voltage regulator controller 202 may make phase and load decisions basedon temperature to better share the loads and minimize these differences.

For each of the individual smart power stages 204, voltage regulatorcontroller 202 may acquire the temperature of the individual smart powerstage 204 in real time, as previously described with reference to FIGS.2A and 2B. Upon acquiring the temperatures of each of the individualsmart power stages 204, voltage regulator controller 202 may calculatetheir average temperature. For each of the individual smart power stages204, voltage regulator controller 202 may determine whether the value ofthe temperature of the individual smart power stage 204 is equal to orgreater than a value of a temperature imbalance threshold. The value ofthe temperature imbalance threshold may be programmable. The value ofthe temperature imbalance threshold may be based on the designparameters of voltage regulator controller 202, monitoring smart powerstage 204 information over time, amongst other considerations. Inanother embodiment, the value of the temperature imbalance threshold mayfurther include an average temperature of the individual smart powerstages 204, e.g. the temperature imbalance threshold may be equal to avalue of a programmable imbalance threshold plus the averagetemperature, where the average temperature may be a calculated value.

When the value of the temperature of the individual smart power stage204 is less than the value of the temperature imbalance threshold,voltage regulator controller 202 may wait a first delay value beforemonitoring and acquiring a new temperature of each individual smartpower stage 204 of the plurality of smart power stages 204 for phase tophase temperature balance control of the plurality of smart power stages204. When the value of the temperature of the individual smart powerstage 204 is equal to or greater than the value of the temperatureimbalance threshold, voltage regulator controller 202 may reduce a dutycycle of the phase corresponding to the individual smart power stage 204and adjust each duty cycle of each of the plurality of the other phasescorresponding individual smart power stages 204 according to atemperature balance control policy. Voltage regulator controller 202 maythen wait a second delay value before monitoring and acquiring a newtemperature of each individual smart power stage 204 of the plurality ofsmart power stages 204 for phase to phase temperature balance control ofthe plurality of smart power stages 204.

By performing phase to phase temperature balance control of theplurality of smart power stages 204 in this manner, may provideincreased temperature margin for an information handling systemincluding an application of a multi-phase voltage regulator 200 coupledto the information handling system in limited or non-existent airconditioning equipment environment, such as a modular datacenterenvironment. This may also result in more cost effective voltageregulator designs for various information handling systems, e.g. aserver or a workstation, by enabling a reduction in a number of phasesin the switching cycle.

In one or more embodiments, voltage regulator controller 202 may utilizethe temperature of each individual smart power stage 204 of theplurality of smart power stages 204 for the prediction and avoidance ofone or more imminent faults of particular smart power stages 204.Temperature may be a good indicator of imminent faults, where atemperature of an individual smart power stage 204 that exceeds a hightemperature threshold value may result in a failure of the individualsmart power stage 204, loss of power to information handling system, andloss of data in the information handling system. Similar to phase tophase temperature balance control, when the value of the temperature ofthe individual smart power stage 204 is equal to or greater than thevalue of the temperature imbalance threshold, voltage regulatorcontroller 202 may predict an imminent fault of the individual smartpower stage 204. Similarly, when the value of the temperature of theindividual smart power stage 204 has a sudden increase from a previousvalue, voltage regulator controller 202 may also predict an imminentfault of the individual smart power stage 204. Based on this prediction,voltage regulator controller 202 may perform further processing to avoidthe imminent fault. For example, voltage regulator controller 202 maysend a warning to multi-phase voltage regulator 200 that indicates theimminent fault of the individual smart power stage 204; perform loadbalancing to reduce the temperature, among other failure avoidancemethods. Early fault prediction and identification may be provided,while still enabling defined catastrophic failure protection.

Turning now to FIGS. 4A and 4B, a circuit diagram of selected elementsof an embodiment of a multi-phase voltage regulator 400 is illustrated.In FIGS. 4A and 4B, multi-phase voltage regulator 400 is shown in aschematic representation and is not drawn to scale or perspective. It isnoted that, in different embodiments, multi-phase voltage regulator 400may be operated with additional or fewer elements. Multi-phase voltageregulator 400 has similar structure and functionality as multi-phasevoltage regulator 200.

As shown in FIG. 4A, components of multi-phase voltage regulator 400 mayinclude, but are not limited to, a voltage regulator controller 402, aplurality of smart power stages 404, among other components previouslydescribed with reference to FIGS. 2A and 2B. A shared signal line 456 iscoupled between voltage regulator controller 402 and each of theplurality of smart power stages 404. For example, shared signal line 456is coupled between shared control signal output 426 of voltage regulatorcontroller 402 and a plurality of corresponding shared control signalinputs (SCS IN) 440 including shared control signal input 440-1 to 440-4of smart power stages 404-1 to 404-4.Voltage regulator controller 402operates similarly to voltage regulator controller 202 but also utilizesa shared control signal sent to smart power stages 404 via shared signalline 456 for temperature monitoring described in further detail below.Shared signal line may be an identification output line (ID OUT) ofvoltage regulator controller 402, which may be a bidirectionalcommunication line. Voltage regulator controller 402 may receive anidentification signal from a smart power stage 404 allowing it todetermine the smart power stage 404's vendor part identification duringan initialization or configuration phase. During operation, voltageregulator controller 402 may send shared control signals to communicatewith each smart power stage 404.

As shown in FIG. 4B, components of each smart power stage 404 of theplurality of smart power stages 404 may include a detector 442 having aswitch, among other components previously described with reference toFIGS. 2A and 2B. In operation, detector 442 will turn on the switch whena sequence of one or more shared control signals are received at thesmart power stage 404 via shared signal line 456 during a temperaturerequest duration and a sequence of control signals are received at PWMinput 232 of the smart power stage 404 that coincide with reception ofthe sequence of the one or more shared control signals at the smartpower stage 404. The sequence of the one or more shared control signalsmay have a pre-determined number of shared control signals within it,where a sequence including two or more shared control signals may beutilized to avoid noise that may result in a false detection. Detector442 may start a count at zero and count the number of shared controlsignals received that are coincident with the reception of the sequenceof control signals at PWM input 232 to determine when the pre-determinednumber of shared control signals has been reached during the temperaturerequest duration. When the temperature request duration has expired, thecount may be reset back to zero. Detector 442 will turn off the switchafter a pre-determined duration.

When the switch of detector 442 is turned on, the corresponding smartpower stage 404 may send a temperature of smart power stage 404 atTOUT/FLT 234 of corresponding smart power stage 404 to voltage regulatorcontroller 402 via monitor bus 254 during a reporting window, where theduration of the reporting window starts at the falling edge of the lastshared control signal of the sequence of the one or more shared controlsignals control signal received. This reporting window may be set to aduration that allows voltage regulator controller 402 to receive thetemperature before requesting any other smart power stage 404 to reportits temperature, so that the requested smart power stage 404 is the onlyone reporting its temperature on monitor bus 254 during the reportingwindow and does not overlap with any other smart power stage 404reporting its temperature. Operating in this manner, allows voltageregulator controller 402 to control which smart power stage 404 sendsits temperature to controller 402 and to determine that the temperaturereceived at TSENSE 224 via monitor bus 254 corresponds to thatparticular smart power stage 404.

Referring back to FIG. 4A, during operation, voltage regulatorcontroller 402 may send a first sequence of control signals to smartpower stage 404-1 via signal line 252-1. Voltage regulator controller402 may also send a sequence of one or more shared control signals tosmart power stage 404-1 via shared signal line 456 that coincide withsending the first sequence of control signals during a temperaturerequest duration. Sending both the first sequence of control signals andthe sequence of the one or more shared control signals enables smartpower stage 404-1 to send a first temperature of smart power stage 404-1to voltage regulator controller 402 during the reporting window. Inresponse to receiving the first sequence of control signals and thesequence of the one or more shared control signals from voltageregulator controller 402, smart power stage 404-1 will send the firsttemperature of smart power stage 404-1 to voltage regulator controller402 during the reporting window, as described above. Voltage regulatorcontroller 402 may receive the first temperature of smart power stage404-1 from smart power stage 404-1 via monitor bus 254 during thereporting window. Voltage regulator controller 402 may also determinethat the first temperature received by voltage regulator controller 402corresponds to smart power stage 404-1 based on the sequence of the oneor more shared control signals and that voltage regulator controller 402has not requested any other smart power stages 404 to report theirtemperatures during the reporting window. When the reporting windowcloses, voltage regulator controller 402 may then make anothertemperature reporting request in a similar manner as previouslydescribed. The interaction between voltage regulator controller 402 andeach of the smart power stages 404 is shown in more detail in FIG. 5.

Turning now to FIG. 5, a timing diagram 500 of shared signal line, phasesignal line, and monitor bus signals for selected elements of anembodiment of a multi-phase voltage regulator (e.g. multi-phase voltageregulator 400) is illustrated. The top portion of timing diagram 500shows sequences of one or more shared control signals sent by voltageregulator controller 402 to each corresponding smart power stage 404-1(phase 1), 404-2 (phase 2), and 404-3 (phase 3) via shared signal line456. The middle portions of timing diagram 500 show the three sequencesof control signals sent by voltage regulator controller 402 to eachcorresponding smart power stage 404-1, 404-2, and 404-3 via signal lines252-1, 252-2, and 252-3 respectively. The bottom portion of timingdiagram 500 shows the voltage level of monitor bus 254 corresponding tothe reported temperature of each smart power stage 404-1 and 404-2 onmonitor bus 254 during its specific reporting window. For example,voltage regulator controller 402 sends the first sequence of two sharedcontrol signals that coincide with two control signals sent to smartpower stage 402-1 via phase 1 signal line 252-1, as depicted by dottedline arrow 511. Smart power stage 402-1 detects the coincidence of thesecond shared control signal of the first sequence, labeled Pstage 1detection 502 and causes smart power stage 404-1 to send itstemperature, TOUT Pstagel 504, after a short delay, to voltage regulatorcontroller 402 by driving the voltage level of monitor bus 254 during afirst reporting window, as depicted by dotted line arrow 513. Only smartpower stage 404-1 sends its temperature over shared monitor bus 254during the first reporting window. Similarly, voltage regulatorcontroller 402 sends the second sequence of two shared control signalsthat coincide with two control signals sent to smart power stage 402-2via phase 2 signal line 252-2, as depicted by dotted line arrow 515.Smart power stage 402-2 detects the coincidence of the second sharedcontrol signal of the second sequence, labeled Pstage 2 detection 506and causes smart power stage 404-2 to send its temperature, TOUT Pstage2508, after a short delay, to voltage regulator controller 402 by drivingthe voltage level of monitor bus 254 during a second reporting window,as depicted by dotted line arrow 517.

Turning now to FIGS. 6A and 6B, a circuit diagram of selected elementsof an embodiment of a multi-phase voltage regulator 600 is illustrated.In FIGS. 6A and 6B, multi-phase voltage regulator 600 is shown in aschematic representation and is not drawn to scale or perspective. It isnoted that, in different embodiments, multi-phase voltage regulator 600may be operated with additional or fewer elements. Multi-phase voltageregulator 600 has similar structure and functional operation asmulti-phase voltage regulator 400.

As shown in FIG. 6A, components of multi-phase voltage regulator 600 mayinclude, but are not limited to, a voltage regulator controller 602, aplurality of smart power stages 604 including smart power stages 604-1to 604-4, among other components previously described with reference toFIGS. 2A, 2B, 4A, and 4B. Shared signal line 456 is coupled betweenvoltage regulator controller 602 and each of smart power stages 604. Forexample, shared signal line 456 is coupled between shared control signaloutput 426 of voltage regulator controller 602 and the plurality ofcorresponding shared control signal inputs 440 including shared controlsignal input 440-1 to 440-4 of smart power stages 604-1 to 604-4 via acorresponding diode 662 and a corresponding resistor circuit 664-1 to664-4 respectively. Each smart power stage 604 uses a different resistorconnection, also called pin strapping, to distinguish which phasecorresponds to which smart power stage 604. For example, smart powerstage 604-1 uses a 10 k Ohm resistor for resistor circuit 664-1.Similarly, smart power stages 604-2 to 604-4 uses a 20 k Ohm resistor, a30 k Ohm resistor, and 40 k Ohm resistor for resistor circuit 664-2 to664-4 respectively. Voltage regulator controller 602 operates similarlyto voltage regulator controller 402 but only utilizes shared controlsignals sent to the plurality of the smart power stages 604 via sharedsignal line 456 for temperature monitoring described in further detailbelow.

As shown in FIG. 6B, components of each smart power stage 604 of theplurality of smart power stages 604 may include a detector 642 having aswitch, among other components previously described with reference toFIGS. 2A, 2B, 4A, and 4B. In operation, detector 642 will turn on theswitch when a count of a sequence of one or more shared control signalsare received at the smart power stage 604 via shared signal line 456during a temperature request duration matches a pre-defined numbercorresponding to the smart power stage 604. In an exemplary embodiment,the pre-defined number for smart power stages 604-1, 604-2, and 604-3may correspond to the numbers 1, 2, and 3 respectively. Detector 642 maystart a count at zero and count the number of shared control signalsreceived during temperature request duration. When the temperaturerequest duration is reached, detector 642 may determine whether thecount matches the pre-defined number corresponding to its smart powerstage 604. After this determination, the count may be reset back tozero. Detector 642 will turn off the switch after a pre-determinedduration to ensure only one smart power stage 604 reports it temperatureover monitor bus 254 at a time. When the switch of detector 642 isturned on, the corresponding smart power stage 604 may send atemperature of smart power stage 604 to voltage regulator controller 602via monitor bus 254 during a reporting window, where the duration of thereporting window starts when the temperature request duration isreached.

Referring back to FIG. 6A, during operation, voltage regulatorcontroller 602 may send a first sequence of one or more shared controlsignals to smart power stages 604-1, 604-2 and 604-3 via signal line252-1. During the temperature request duration, each detector 642-1,642-2 and 642-3 counts the number of shared control signals received byits corresponding smart power stage 604-1, 604-2, and 604-3. When thetemperature request duration is reached, each detector 642-1, 642-2 and642-3 may determine whether its count matches the pre-defined numbercorresponding to its smart power stage 604-1, 604-2, and 604-3. When thecount of a particular smart power stage 604 matches its correspondingpre-defined number, the particular smart power stage 604 will send thefirst temperature of the matching smart power stage 604 to voltageregulator controller 602 during the reporting window, as describedabove. Voltage regulator controller 602 may determine that the firsttemperature received by voltage regulator controller 602 corresponds tothe matching smart power stage 604 based on the first sequence of theone or more shared control signals and that voltage regulator controller602 has not requested any other smart power stages 604 to report theirtemperatures during the reporting window. When the reporting windowcloses, voltage regulator controller 602 may then make anothertemperature reporting request in a similar manner as previouslydescribed. The interaction between voltage regulator controller 602 andeach of the smart power stages 604 is shown in more detail in FIG. 7.

Turning now to FIG. 7, a timing diagram 700 of shared signal line, smartpower stage falling edge count values, and monitor bus signals forselected elements of an embodiment of a multi-phase voltage regulator(e.g. multi-phase voltage regulator 600) is illustrated. The top portionof timing diagram 700 shows sequences of one or more shared controlsignals sent by voltage regulator controller 602 to each correspondingsmart power stage 604-1 (phase 1), 604-2 (phase 2), and 604-3 (phase 3)via shared signal line 456. The middle portions of timing diagram 700show the falling edge count values of each smart power stage 604-1,604-2, and 604-3. The bottom portion of timing diagram 700 shows thevoltage level of monitor bus 254 corresponding to the reportedtemperature of each smart power stage 604-2 and 604-3 on monitor bus 254during its specific reporting window. For example, voltage regulatorcontroller 602 sends the first sequence of two shared control signals tosmart power stages 604-1, 604-2, and 604-3 via shared signal line 456,as depicted by dotted line arrow 711. Each smart power stage 604 detectsthe falling edge of the first shared control signal of the firstsequence and increases its count from zero to one, depicted by dottedline arrows 713. Similarly, each smart power stage 604 detects thefalling edge of the second shared control signal of the first sequenceand increases its count from one to two, depicted by dotted line arrows715 during the temperature request duration. When the temperaturerequest duration has been reached, smart power stage 604-2 determinesthat its corresponding number matches its count of two, labeled Pstage2match 702, and causes smart power stage 604-2 to send its temperature,TOUT Pstage2 704, to voltage regulator controller 602 by driving thevoltage level of monitor bus 254 during a first reporting window, asdepicted by dotted line arrow 717. Only smart power stage 604-2 sendsits temperature over shared monitor bus 254 during the first reportingwindow.

Similarly, voltage regulator controller 602 sends the second sequence ofthree shared control signals to smart power stages 604-1, 604-2, and604-3 via shared signal line 456, as depicted by dotted line arrows 719.Each smart power stage 604 detects the falling edge of the first,second, and third shared control signals of the second sequence andincreases its count from zero, to one, to two, to three, depicted bydotted line arrows 721, 723, and 725 respectively during the temperaturerequest duration. When the temperature request duration has beenreached, smart power stage 604-3 determines that its correspondingnumber matches its count of three, labeled Pstage3 match 706, and causessmart power stage 604-3 to send its temperature, TOUT Pstage3 708, tovoltage regulator controller 602 by driving the voltage level of monitorbus 254 during a second reporting window, as depicted by dotted linearrow 727. Only smart power stage 604-3 sends its temperature overshared monitor bus 254 during the second reporting window.

Referring now to FIG. 8, a block diagram of selected elements of anembodiment of a method for individual phase temperature monitoring andbalance control in a smart power stage based multi-phase voltageregulator (such as multi-phase voltage regulator 200) is depicted inflowchart form. It is noted that certain operations described in method800 may be optional or may be rearranged in different embodiments.

The multi-phase voltage regulator may include a plurality of smart powerstages including a first smart power stage and a second smart powerstage. The multi-phase voltage regulator may also include a controllercoupled to: the first smart power stage by a first signal line and ashared monitor bus, and the second smart power stage by a second signalline and the shared monitor bus.

Method 800 may begin at step 802, sending, by the voltage regulatorcontroller, a first control signal to the first smart power stage viathe first signal line to enable the first smart power stage to send afirst temperature of the first smart power stage to the voltageregulator controller during a first phase of a switching cyclecorresponding to the first smart power stage. At step 804, determiningthat the first temperature received by the voltage regulator controllervia the shared monitor bus corresponds to the first smart power stagebased on the first control signal. At step 806, sending a second controlsignal to the second smart power stage via the second signal line toenable the second smart power stage to send a second temperature to thevoltage regulator controller during a second phase.

Referring now to FIG. 9, a block diagram of selected elements of anembodiment of a method for temperature balance control in a smart powerstage based multi-phase voltage regulator (such as multi-phase voltageregulators 200, 400 and 600) is depicted in flowchart form. It is notedthat certain operations described in method 900 may be optional or maybe rearranged in different embodiments.

The multi-phase voltage regulator may include a plurality of smart powerstages including a first smart power stage and a second smart powerstage. The multi-phase voltage regulator may also include a controllercoupled to: the first smart power stage by a first signal line and ashared monitor bus, and the second smart power stage by a second signalline and the shared monitor bus.

Method 900 may begin at step 902, acquiring, for each of the individualsmart power stages, the temperature of the individual smart powerstages. At step 904, the method may calculate the average temperature ofthe individual smart power stages. At step 906, for each of theindividual smart power stages, determining whether the value of thetemperature of the individual smart power stage is equal to or greaterthan a value of a temperature imbalance threshold. At step 908, waiting,when the value of the temperature of the individual smart power stage isless than the value of the temperature imbalance threshold, a firstdelay value before acquiring a new temperature of each individual smartpower stage. At step 910, reducing, when the value of the temperature ofthe individual smart power stage is equal to or greater than the valueof the temperature imbalance threshold, a duty cycle of the phasecorresponding to the individual smart power stage and adjust each dutycycle of each of the plurality of the other phases corresponding to theindividual smart power stages according to a temperature balance controlpolicy. At step 912, waiting a second delay value before acquiring a newtemperature of each individual smart power stage.

Referring now to FIG. 10, a block diagram of selected elements of anembodiment of a method for individual phase temperature monitoring andbalance control in a smart power stage based multi-phase voltageregulator (such as multi-phase voltage regulator 400) is depicted inflowchart form. It is noted that certain operations described in method1000 may be optional or may be rearranged in different embodiments.

The multi-phase voltage regulator may include a plurality of smart powerstages including a first smart power stage and a second smart powerstage. The multi-phase voltage regulator may also include a voltageregulator controller coupled to: the first smart power stage by a firstsignal line, a shared signal line, and a shared monitor bus, and thesecond smart power stage by a second signal line, the shared signalline, and the shared monitor bus.

Method 1000 may begin at step 1002, sending, by the voltage regulatorcontroller, a first sequence of one or more control signals to the firstsmart power stage via the first signal line. At step 1004, sending asecond sequence of one or more shared control signals that coincide withthe first sequence of one or more control signals to the plurality ofsmart power stages via the shared signal line to enable the first smartpower stage to send a first temperature of the first smart power stageto the voltage regulator controller during a first reporting window. Atstep 1006, determining that the first temperature received by thevoltage regulator controller via the shared monitor bus corresponds tothe first smart power stage based on the second sequence of the one ormore shared control signals. At step 1008, sending a fourth sequence ofone or more shared control signals that coincide with a third sequenceof one or more control signals to the plurality of smart power stagesvia the shared signal line to enable the second smart power stage tosend a second temperature of the second smart power stage to the voltageregulator controller during a second reporting window.

Referring now to FIG. 11, a block diagram of selected elements of anembodiment of a method for individual phase temperature monitoring andbalance control in a smart power stage based multi-phase voltageregulator (such as multi-phase voltage regulator 600) is depicted inflowchart form. It is noted that certain operations described in method1100 may be optional or may be rearranged in different embodiments.

The multi-phase voltage regulator may include a plurality of smart powerstages including a first smart power stage and a second smart powerstage. The multi-phase voltage regulator may also include a voltageregulator controller coupled to: the first smart power stage by a sharedsignal line and a shared monitor bus, and the second smart power stageby the shared signal line and the shared monitor bus.

Method 1100 may begin at step 1102, sending, by the voltage regulatorcontroller, a first sequence of a first number of shared control signalsto the plurality of smart power stages via the shared signal line toenable the first smart power stage corresponding to the first number tosend a first temperature of the first smart power stage to the voltageregulator controller during a first reporting window. At step 1104,determining that the first temperature received by the voltage regulatorcontroller via the shared monitor bus corresponds to the first smartpower stage based on the first sequence of the first number of sharedcontrol signals. At step 1106, sending a second sequence of a secondnumber of shared control signals to the plurality of smart power stagesvia the shared signal line to enable the second smart power stagecorresponding to the second number to send a second temperature of thesecond smart power stage to the voltage regulator controller during asecond reporting window.

The above disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments which fall within thetrue spirit and scope of the present disclosure. Thus, to the maximumextent allowed by law, the scope of the present disclosure is to bedetermined by the broadest permissible interpretation of the followingclaims and their equivalents, and shall not be restricted or limited bythe foregoing detailed description.

What is claimed is:
 1. A multi-phase voltage regulator, comprising: aplurality of smart power stages including a first smart power stage anda second smart power stage; and a controller coupled to: the first smartpower stage by a first signal line and a shared monitor bus, and thesecond smart power stage by a second signal line and the shared monitorbus, the voltage regulator controller to: send a first control signal tothe first smart power stage via the first signal line to enable thefirst smart power stage to send a first temperature of the first smartpower stage to the voltage regulator controller during a first phase ofa switching cycle corresponding to the first smart power stage;determine that the first temperature received by the voltage regulatorcontroller via the shared monitor bus corresponds to the first smartpower stage based on the first control signal; and send a second controlsignal to the second smart power stage via the second signal line toenable the second smart power stage to send a second temperature to thevoltage regulator controller during a second phase.
 2. The multi-phasevoltage regulator of claim 1, the voltage regulator controller furtherto: determine that the second temperature received by the voltageregulator controller corresponds to the second smart power stage basedon the second control signal.
 3. The multi-phase voltage regulator ofclaim 1, the first smart power stage further comprising: a first switchto send the first temperature to the voltage regulator controller basedon a rising edge of the first control signal.
 4. The multi-phase voltageregulator of claim 3, wherein the first switch is controlled by amono-stable multi-vibrator.
 5. The multi-phase voltage regulator ofclaim 1, the voltage regulator controller further to: determine whetherthe first temperature of the first smart power stage is equal to orgreater than a value of a temperature imbalance threshold; and when thefirst temperature is equal to or greater than the value of thetemperature imbalance threshold, reduce a first duty cycle of the firstphase and adjust each duty cycle of each of the plurality of the otherphases according to a temperature balance control policy.
 6. Themulti-phase voltage regulator of claim 5, wherein the value of thetemperature imbalance threshold further includes an average of eachtemperature of each smart power stage of the plurality of smart powerstages.
 7. The multi-phase voltage regulator of claim 1, the voltageregulator controller further to: determine whether the first temperatureof the first smart power stage is equal to or greater than a value of atemperature imbalance threshold; and when the first temperature is equalto or greater than the value of the temperature imbalance threshold,send a warning that indicates an imminent fault of the first smart powerstage.
 8. The multi-phase voltage regulator of claim 1, wherein thefirst control signal is a pulse width modulated signal.